I have absolutely no documentation of any sort for the Prisma 40 so what follows is all based on working with the one incomplete example that I have. It is incomplete in that the power supply was missing along with some of the internal pillars that support the two circuit boards. I guess that it originally used a similar switched-mode PSU to the 020 based Prismas but since I only have one of those, I have adapted an old PC PSU to power my 040 box.
Just to confuse matters, the 020 and 040 models are both labeled as "Model 700" and are housed in almost identical cabinets. The main difference being the layout of the connectors on the back panel.
The basic hardware spec of the model 700 workstation is:
Width 540mm / 21.25in Height 115mm / 4.5in Depth 425mm / 16.75in Weight 12.6kg / 28lb Processor CPU 68040 at 25MHz Memory 8MB RS-232 ports 4 (tablet/mouse, joystick, modem/printer, data terminal) Keyboard port 5-pin DIN for a PC style keyboard Video Output RGB, sync on green Resolution 1280 x 1024 Planes 9 ?? Vert. sync 60Hz Horiz. sync 63.9KHz Dot clock 110MHz Network Ethernet AUI or BNC (on-board transceiver)
The basic workstation comprises the chassis, with power supply and fans, and two large circuit boards. The "Graphics Controller", which is the main CPU card, and the "Video Buffer", which contains all the video memory and display logic. The two boards are linked by two ribbon cables. Both boards make extensive use of programmable logic devices and gate arrays which presents a challenge when trying to write device drivers!
The video buffer is an unknown quantity at present, I think that it retains hardware line-drawing for compatibility with the earlier systems but also that it is now accessible as a framebuffer. Hopefully I will be able to figure out how it works as time goes on.
The 68040 appears to be used to drive the Ethernet and graphics only, all the serial I/O is handled by a separate 68302 processor. the two processors communicate through a dual-port SRAM chip.
CPU MC680040RC at 25MHz SRAM 128KB of static RAM using 8 x TC55465J-20 DRAM 8MB of DRAM, TC511000AZ and TC514400AZ Shared mem IDT 71321SA 2K x 8 dual-port SRAM EEPROM B14293C66N 256 x 16bit Ethernet Intel 82596CA-25 I/O CPU MC68302FE16 UART SCN68681C1A44 Video DAC Bt 459KG110 RAMDAC